Photo-electric tube



Nov. 29, 1932. F. A. BERG ET AL 1,889,431

PHOTO ELECTRIC TUBE Nov. 29, 1932. F. A. BERG ET AL PHOTO ELECTRIC TUBE Filed July l2. 1929 2 Sheets-Sheet 2 Patented Nov. 29, 191324 UNITED lSTATES FREDERICK A. BERG ANDWILLIAM w. Hanrnnon CHICAGO, ILLINoIs pHoro-ELECTRIC TUBE Application led Ju1y 12,

This invention relates to an improved multi-cathode photo-electric vessel and has for one of its principal objects the provision of a light sensitive vessel which will have a plurality of cathodes therein for special purposes.

One of the important objects of this 1nvention is to provide in a photoelectrical vessel a plurality of light sensitive elements intended for the selective control of various types of complex electrical net-works. n

Another important ob]l ect of this invention is to provide in a photo-electric vessel means for controlling a selective relay net-work so disposed as to permit distribution of sound and other impulses to various points either simultaneously or in a regulated sequence.

Other and further important objects of the invention will be apparent from the disclosures in the accompanying drawings and following specification.

The invention, in a preferred form, is illustrated in the drawings, and hereinafter more fully described.

In the drawings:

Figure 1 is a front elevation of the improved multi-cathode photo-electric vessel of this invention.

Figure 2 is an enlarged fragmentary top plan View of the interior thereof.

Figure 3 is a central cross sectional view of the same. Y

Figure 4 shows a modied form of construction.

Figure 5 is a detail view of a portion of Figure 4.

As shown in the drawings: v v

The reference numeral 10 indicates generally the glass envelope in which the elements of this photo-electric vessel are disposed. These elements comprise essentially a plurality of catliodes 12 which as shown are twent -four in number, but which number can o viously be changed as desired or convenient. Any number of these vessels can be connected in series or parallel. v

The cathodes are supported upon one face of a mica strip 14, each cathode being electrically connected to a lead-in wire 16, all

o of which pass out through suitable sealed 1.929. seriai No. 377,880.

lead-in elements -18 at both ends of the vessel 10. The wires are insulated by baked enamel, which eliminates occlusion of gases.y p f Also mounted in each of these lead-in elements is a support 2O preferably composed of 55 comparatively heavy wire by means of which the mica strip 14 is mounted in proper position in the vessel, and a further support 22 is Vprovided sealed into the bottom of the vessel which assists in maintaining proper positioning of the mica strip and its cathodes. In practice the mica strip 14 is madel in two sections, and each section with its supporting wire 20 is slipped into the open end of the tube before the same is sealed-and the 55 innerends are aligned upon the support 22 so that these two parts form substantially the equivalent of one long mica strip. It will be noted that the vessel although substantially tubular has one portion thereof ilattened as shown atk26, this providing a plane windowthrough which rays of light enter for impinging upon oneor more 'of the cathodes 12.

This device can be used inthe operation of invention entitled ,Motion picture screen and sound box filed by applicant, Frederick A. Berg, November 30, 1928, Serial No. 322,863. It is also adaptable for remote control of various appliances.v The double window feature illustrated in Figure 4, makes one side always available in any emergency.

After the vessel has. been assembled as shown, it is connected to a vacuum system in the usual manner by means of an opening providedat the point 28, and when the vacu- .uni reachesa suitable degree, the inner wall of the vessel is completely coated with a me tallic deposit 30 of some photo-active metal in any well-known manner.V This may be :easily accomplished by meansof distillation, and duriiigthis process the studs or cathodes being of metal 'are also coated with this photo-active metal. When a suiciently heavy coat of metal has been deposited, the distillation isstopped, and then a small flame -providing suicie'nt `heat to melt the inner metal coating is next applied to the flattened window 26, and in this manner, the inner coating is removed as shown at 32 in Figure 1 so as to permit controlling light beams to be directed upon the photo-active studs or cathodes l2.

The process is then continued to completion in the ordinary manner such as by activating the vessel and maintaining it in this state or by the further introduction of hydrogen, argon, neon or some similar gas, the vessel being then sealed off at the point 28. A small well 38 holding a lead wire 40 for the anode connection is sealed into the end of the vessel opposite the exhaust point 28.

It will be evident that the activating of the cathode studs by means of beams of light will permit current to flow between the anode wire 40 and one or more of the cathode wires 16. In this way, any one or more of a connected series of relays may be operated whereby various effects in sound and light distribution can be obtained. This can ybe particularly applied to a talking motion picture system and also to the control of organs and other musical equipment. Further possibilities are found in the design of automatically recording stock exchange boards, and for many other purposes wherein selective control of one or more of a plurality of instruments is desired by means of light rays.

In a talking motion picture studio, a separate band of iilm adjacent the motion picture lm is constructed so as to permit light beams of varying duration and intensity and of certain spaced relation to pass therethrough and impinge upon one or more of the cathodes in a certain sequence. Besides operating relays in a predetermined order, it will be evident that inasmuch as the intensity of the light rays can be varied by shaded gradations on the film, corresponding intensity of action can be had with the relays.

In the modification shown in Figures 4 and 5, a greater number of cathodes are provided as illustrated at 42, and from an inspection of Figure 5, it will be evident that these cathodes are square in shape thereby providing a greater area for the light ray impact.

It will be further evident that two banks of thirty cathodes each are provided, each bank separated on a strip of mica or the like 44. The mica strips themselves are maintained in position by means of end rods 46 and center supports 48.

Opposite each bank of cathodes is a flattened window 50 from which the alkali metal, such as potassium hydride or other coating has been removed, this coating, which forms the anode, remaining on the adjacent walls of the vessel as illustrated at 52.

We are aware that many changes may be made and numerous details of construction varied throughout a wide range without departing from the principles of this invention, andwe therefore do not purpose limiting the tures.

FREDERICK A. BERG. WILLIAM W. HARPER. 

